Clock signals and timing signals generated by a resistor-capacitor (RC) oscillator may be provided to various electronic circuits such as a micro processor, a micro controller, a flip-flop circuit, a latch circuit and the like. The RC oscillator has been extensively used in the electronic industries due to its fundamental function of generating clock and time signals.
Generally, in mobile devices using a battery such as a portable flat panel display, a mobile communication device and the like, a low power-consumption RC oscillator is required to increase the battery life after charging the battery once. Especially, as the resolution of the display screen increases, the number of pixels of the display screen also increases. In such a case, the power consumption of the RC oscillator is increased in proportion to a square of the power supply voltage. Thus, there has been a strong demand for an RC oscillator operating in low power consumption in the relevant field.